Well, when Ferguson took over half way through the 1986/87 season, the club had 7 league titles, 1 European Cup (no other Euros) and 6 FA Cups (no league cups). Pretty good, but not even close to the number of cups at the Anfield museum. As John Bishop said; "We have so many cups we use them as egg cups".
Another thing is the fact that things change over time. Back then (1986) people tended to be more patient than they do today. The demand for instant success is huge, and the media doesn't exactly slow down that sensation...